The present invention relates to integrated telephone transmission and switching systems and more particularly to a subscriber switch controller for enabling connections between a plurality of local subscriber liens and a central office.
In the cross-referenced application entitled "Integrated Transmission and Switching System," there is provided therein a system for making digital connections between local subscriber lines and any other line in the telephone system. That system includes a control office base switch connected to a plurality of multitime-slot digital data buses, commonly known as T-1 lines, for interconnecting with the outside world and with a plurality of local subscriber lines. The system operation in multiframe format of 12 frames where each frame includes 24 time slots having a periodic frame rate of 125 .mu.sec. Each time slot has 8 bits of sampled information to digitally represent the analog information in pulse code modulated (PCM) format.
To make connections between a local level and any time slot in the telephone system, a subscriber switch is provided therein for connecting and concentrating a plurality of local subscriber lines to a pair of T-1 lines, which enables the base switch to make the interconnections to any time slot in the system.
In order to connect a plurality of local subscriber lines to the base switch, there is a need for a subscriber switch controller that will enable the interconnections and concentrations of the subscriber lines to specified time slots on the pair of T-1 lines.
In view of the above background, it is an object of the present invention to provide a subscriber switch controller for enabling connections between a plurality of subscriber lines and specified time slots on a multitime-slot digital data bus such as a T-1 line, thereby enabling digital connections from a local level to any subscriber line in the telephone system.